Issue: September 29, 2007

Yellow mushroom in potted plant / Can I compost tree leaves with fungus disease?

Yellow mushroom in potted plant

A friend asked me this morning about a problem with her Jade plant. It has a light yellow mushroom fungus in the soil. The mushrooms are about three inches tall. She repotted it about a year ago. The pot is about 1 and a half feet tall and 20 inches across. I didn't ask her how often she waters.

I love this tree. Is there anything I can do to help it recover?

P. D.
Lea County

Answer:

The yellow mushroom you described is probably one that is common in store-bought potting soils. It will probably not harm the jade plant, unless the jade plant is overwatered. This fungus is the fruiting structure of a fungus that helps make compost. The fact that the mushroom is growing may indicate that the jade plant is overwatered and that the compost is still decomposing.

To prevent problems, the soil should dry well between waterings. However, this may cause the soil to shrink and pull away from the side of the pot. Soil shrinkage may make it difficult to remoisten the soil the next time you water because the soil won't absorb moisture after it dries (water will run around the soil). In that case, moisten the potting soil by watering from the bottom. Once the soil has become moist, allow surplus water to drain away. (Don't let the bottom of the pot remain in the water and don't fail to let surplus water drain - these mistakes can cause root rot.)

Can I compost tree leaves with fungus disease?

If my tree has a leaf fungus, is it safe to put the leaves into my compost? I have always heard that you shouldn't put diseased plant material into the compost.

Answer:

It may be safe to compost leaves from a tree with leaf fungus if the disease isn't one that affects a wide range of plants. Take a sample of the diseased leaf to your County NMSU Extension Service office to have the disease identified. Then you will know if the disease is a danger to other plants.

The reason people are advised not to compost diseased plant material is to prevent reintroducing the disease into a garden the next year when the compost is used. If the disease on the leaves isn't a concern for vegetable or flowers, then the compost can be safely used in the garden. Properly-made compost should naturally heat to a temperature that kills most of the fungal spores. Removing diseased leaves from under the tree reduces the chance for reinfesting the tree next year because the fungal spores in the leaves were removed. By composting the leaves, many of the spores are killed, further reducing the opportunity for them to reinfest the tree next year.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.

For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms and the NMSU Horticulture Publications page.

Send gardening questions to Southwest Yard and Garden - Attn: Dr. Marisa Thompson at desertblooms@nmsu.edu, or at the Desert Blooms Facebook.

Please copy your County Extension Agent and indicate your county of residence when you submit your question!